(1) Field of the Invention
This invention relates to high-pressure tank apparatuses in which high-pressure gas charged in a high-pressure tank is taken out thereof following pressure reduction by a reducing valve, and particularly relates to arrangements of the reducing valve.
(2) Background Art
There are known conventional high-pressure tanks in which gas, such as hydrogen gas or natural gas, is charged and stored at a high pressure of 7 MPa to 75 MPa. Since the gas in such a tank is at a high pressure, the high-pressure gas is reduced in pressure by a reducing valve in order to be at a low pressure for use. The reducing valve is connected to a shut-off valve in series to form a valve mechanism. The valve mechanism, having both the valves, is generally attached externally to the high-pressure tank in a manner to be connected to a gas outlet of the tank.
However, if the valve mechanism is placed externally of the tank, a tank apparatus constructed by combining the tank with the valve mechanism is inevitably great in size as a whole, and there is a limit to its downsizing.
Furthermore, since the valve mechanism is placed externally of the tank, it is easy to hit on nearby things and may be thereby damaged, for example, when carried somewhere. The damage may cause the high-pressure gas to blow out of the tank.
Moreover, the above structure requires to connect the tank to the valve mechanism via high-pressure piping. This involves seals at the connecting points of the high-pressure piping and the like in order to prevent the leakage of high-pressure gas therefrom. In consideration of such a sealing structure against high pressure, close attention must be paid to the handling of the valve mechanism, the high-pressure piping and the like.
Therefore, an object of the present invention is to improve the arrangement of the valve mechanism including a reducing valve for reducing gas pressure in the high-pressure tank as described above to thereby downsize the tank apparatus as a combination of the tank and the valve mechanism, prevent damage to the valve mechanism and facilitate the handling of the valve mechanism and the like.
To attain the above object, in the present invention, the valve mechanism is of a built-in type in which the valve mechanism is accommodated in the high-pressure tank.
Specifically, according to the present invention, a high-pressure tank apparatus comprises a high-pressure tank in which high-pressure gas is charged, and a valve mechanism provided at a gas outlet of the high-pressure tank to locate inside of the tank. Furthermore, the valve mechanism comprises a shut-off valve for providing and interrupting communication between the inside and outside of the tank by its opening and closing, respectively, and a reducing valve connected to the shut-off valve in series for reducing the pressure of the high-pressure gas in the tank.
With the above arrangement, when the shut-off valve of the valve mechanism is opened, the inside of the high-pressure tank is communicated with the outside, the high-pressure gas charged in the tank flows through the reducing valve series-connected to the shut-off valve, the high-pressure gas is pressure reduced to a low pressure by the reducing valve, and the resultant low-pressure gas is then discharged to the outside of the tank.
In this case, the valve mechanism is of an in-tank structure in which it is provided at the gas outlet of the high-pressure tank to locate inside of the tank. Therefore, the tank apparatus as a combination of the high-pressure tank and the valve mechanism has the same size as the high-pressure tank itself, resulting in a downsized tank apparatus.
Furthermore, since the valve mechanism is located inside of the high-pressure tank, it can be protected by the high-pressure tank. This prevents the valve mechanism from hitting on nearby things and thereby being damaged when the high-pressure tank is carried somewhere or at other time.
Moreover, low-pressure gas obtained as the result of pressure reduction through the valve mechanism in the high-pressure tank is taken out from the high-pressure tank. This eliminates the need for such a sealing structure against high pressure provided externally of the tank as required when high-pressure gas is taken out from the high-pressure tank as it is, and reduced in pressure, thereby enhancing the handleability of the valve mechanism and the like.
The valve mechanism preferably has a structure which includes a capsule fixedly attached to the gas outlet in a gas-tight manner to face the inside of the high-pressure tank and in which the shut-off valve and the reducing valve are arranged within the capsule. With this structure, the capsule can accommodate the shut-off valve and the reducing valve with its inner space put under an atmospheric pressure like the outside of the tank. This facilitates the arrangement of these valves.
Furthermore, the high-pressure tank preferably includes a tank body made of aluminium or resin, and a covering member for covering the outer periphery of the tank body for reinforcement. With this structure, a light and compact high-pressure tank apparatus can be obtained.
Moreover, the gas pressure in the high-pressure tank is preferably set at 7 MPa to 75 MPa. In this manner, there can be obtained an optimal high-pressure tank which effectively exhibits the effects of the invention.
Moreover, the gas is preferably hydrogen gas or natural gas. Thus, a suitable gas can be obtained.